Field of Invention
The present invention relates to a liquid crystal display field, and more particularly to a COA array substrate and a display device.
Description of Prior Art
Flat liquid crystal display devices, such as liquid crystal displays (LCDs), have advantages of high quality, power saving, a thin structure, and a wide application. Accordingly, the liquid crystal display devices are widely utilized in various consumer electronic products, e.g., mobile phones, televisions, personal digital assistants, digital cameras, notebooks, desktop computers, and they become mainstream display devices. Currently, most of the liquid crystal display device on the market are backlight type liquid crystal display devices, and each comprises a thin film transistor liquid crystal display (TFT-LCD) panel and a backlight module. An operating principle of the liquid crystal display panel is to place liquid crystal molecules between two glass substrates which are parallel with each other. Vertical and horizontal fine wirings are disposed between the two glass substrates. Orientations of the liquid crystal molecules are controlled to be changed by providing electricity. An image is generated by refracting light from the backlight module. In-cell capacitance screens, which integrate a touch function with internal units, become increasingly popular because of advantages that the display panels can be thinned and outdoor visibility can be increased. In a traditional panel design and an in-cell design, at least two additional layers are required to include touch sensors manufactured thereon, and thus manufacturing cost is increased. In a traditional pixel design, a black matrix (BM) is utilized to shade light. However, the black matrix is positioned on a color filter (CF) substrate. When a curved display device is bent, a problem that an upper substrate and a lower substrate are misaligned with each other might occur. Accordingly, a risk of light leakage exists, a panel, which is normal in a flat state, has mura phenomenon in a curved state.
To solve the problem, a DBS (Data Line BM Less) pixel design is utilized more and more in a curved display panel. In this design, ITO (Indium Tin Oxide) wirings cover data lines. A width of each of the ITO wirings is slightly wider than a width of each of the data lines. The ITO wirings are connected to common electrodes. When the panel is operated normally, an electric field generated by the ITO wirings and the common electrodes can control the liquid crystal molecules not to be oriented, so as to achieve an objective of shading the light. Furth, this design has an advantage that the ITO wirings utilized for shading the light are positioned on a TFT substrate (i.e., an array substrate). When the panel is manufactured as a curved display device and the curved display device is bent, positions of the ITO wirings are not changed relative to positions of the data lines. As a result, the problem of the light leakage does not exist.
FIG. 5 is a DBS pixel design of wirings of common electrodes in a display area in the prior art. FIG. 5 shows a mesh structure. The wirings of the common electrodes 4 in a vertical direction have a light shading function for data lines. The wirings of the common electrodes 6 in a horizontal direction are connected to the wirings of the common electrodes 4 in the vertical direction to form the mesh structure, so as to ensure stability of a voltage of a common signal.
FIG. 4 is a cross-sectional view of a DBS pixel including a data line 1 in the prior art. The pixel is manufactured on a COA (color filter on array) substrate on which a color filter is manufactured. A wiring of a common electrode 4 in the vertical direction is positioned above the data line 1, and its width is greater than a width of the data line 1. A pixel electrode 5 includes light transmitting areas at two sides of the data line 1. Since the common electrode 4 in the vertical direction and the pixel electrode 5 are manufactured of the same metal layer, a minimum distance S1 between the common electrode 4 and the pixel electrode 5 is required to prevent a short circuit. Accordingly, an area of the pixel electrode 5 is limited, and an aperture ratio and a transmittance are difficult to be increased.